A glance through the classified section in one of Tanzania's national newspapers can reveal a bewildering selection of items for sale.

Pregnant dairy cows, drums of bitumen and even a petrol station in the centre of the commercial capital, Dar es Salaam, are available for the discerning buyer.

But what almost all the advertisements have in common is the method of contact for those with something to sell - a mobile phone number.

It is a measure of how the communications industry is transforming Tanzania that access to a mobile phone can mean the difference between winning or losing a sale.

Supporting this growing appetite for access to mobile networks is a new breed of entrepreneur.

"We like phones"

In the dusty centre of Kigoma, a remote northern border town on the shores of Lake Tanganyika, close to Burundi and Rwanda, Theo Mbaye sells air time vouchers for pre-pay mobile phones from his brightly painted wooden kiosk.

Even in some remote villages, mobile vouchers are available

As bank accounts are still the preserve of a minority of Tanzanians, especially in rural areas, most people prefer to pay up front in cash for access to phone networks.

A former taxi driver, Mr Mbaye has run his kiosk for the past year and, despite some concerns, finds business is better than in his previous career.

"Many people use mobile phones in Kigoma, we like mobile phones here. It's a good job, but the problem is getting enough vouchers to buy so I can sell them on," he says.

Reliable service

Competition is also strong, with many of the town's bars, shops and even hair salons doubling up as mobile phone voucher outlets.

A lot of individual entrepreneurs are finding independence by selling vouchers or setting up public phone spots

Lara Srivastava, International Telecommunications Union

Outside Kigoma the story is much the same. Stores in the villages that straddle the region's often precarious dirt roads are as likely to display a mobile phone company logo as a sign for water or fuel.

The reason for this is simple. Tanzania's three main mobile operators, Vodacom, Celtel and Mobitel, offer something the country's older fixed-line company has long failed to supply, a reliable telecoms service.

Vodacom estimates that there are around 25,000 locations across Tanzania selling its vouchers and phones.

But with the majority of Tanzanians living on less than $1 a day, buying a phone voucher can cost almost a week's wages.

Cheaper calls

Not far from Mr Mbaye's kiosk, a metal container housing six telephones connected to Vodacom's mobile network offers a less expensive way to make calls.

Known as Simu ya watu, or People's Phone, calls from the container - essentially a glorified phone box - start at 300 shillings (29 US cents) per minute.

Simu ya watu is one way of making access to phones easier

The service may not be physically mobile, but owner and manager Mwilima Ahmed Kalunga says it is proving popular among users.

"Mostly we have fishermen here, we have farmers and we have the business community," he says. "The business community comprises of people from other countries and other districts. These are the main users of Simu ya watu."

A local-born businessman, Mr Kalunga was keen that the metered service - popular in other parts of Tanzania - be introduced in Kigoma. "We thought that Kigoma was being left behind as far as communications are concerned", he says.

However, buying the container from Vodacom was not cheap.

"It cost $13,000," he says. "But most people like to use us because they can see the minutes tick. They cannot be cheated."

Street traders

The increasing number of mobile entrepreneurs reflects the growing importance of the industry in Africa, says Lara Srivastava, a telecoms policy analyst with the Swiss-based International Telecommunications Union.

"It is a lucrative business. A lot of individual entrepreneurs are finding independence by selling vouchers or setting up public phone spots," she says.

"It's still rather on the expensive side, but things are going to change. Prices will go down. People can spend only what they want and what they can afford."

Telecoms are playing a bigger role in Tanzanian life

Unlike Simu ya watu, many public phone spots are not licensed by the likes of Vodacom and Celtel and are run by people who simply have a mobile phone in their hand.

Dotted around some of the bigger roadside villages, crudely painted versions of the mobile operators' logos attempt to lend authenticity to these street traders.

"They are resellers, basically," says Ms Srivastava. "Because things are so expensive, there is a lot of demand. Often it's unregulated, but the operators still benefit because calls are being made."

However, in Kigoma Mr Kalunga believes his telecoms business can make a positive difference to the lives of the people living there.

Using some of the profits from his family-run phone business, he hopes eventually to build a new and much-needed primary school in the town.